Threading-die and holder.



H. VI. LOOMER THREADlNG DIE AND HOLDER.

APPLICAHON HLED JUNE14, i915.

\ /M/ENTU/ HENRY M. LOOMER, OF BEVERLY, MASSACHUSETTS.

THREADING-DIE AND HOLDER.

Application led June 1t, 1915.

To all whom t may concern Be it known that I, HENRY M. LOOMER, a citizen of the United States, residing at Beverly, in the county of Essex and State of Massachusetts, have invented certain Improvements in Threading-Dies and Holders, of which the following description, in connection with the accompanying drawings, is a specification, on the drawings indicating like parts in the several figures.

This invention relates to improvements in threading dies and holders therefor.

An object of this invention is to produce a compact threading die and holder which shall be economical in use and which, while combining the clean cutting and resharpening features of the ordinary form of spring die, will possess the rigidity of a solid die.

A further object of the invention4 is to provide, in a pronged die having the above characteristics, means for adjusting the cutting edges of the die with great accuracy so that in every adjustment of the die each of the cutting prongs will do its proportionate share of the cutting and maintain the accuracy of the lead of the screw thread.

Other objects and features of the invention will be apparent when the following description and claims are considered in connection with the accompanying drawings, in which- Figure 1 is a separated View of one form of die according to the present invention, together with a clamping thimble for securing it in a die holder; Fig. 2 is an assembly view, partly in section, of the die and thimble shown in Fig. 1, together with a holder and improved cap for the same; Fig. 3 shows another form of die according to the present invention: Fig. 4 is an assembly View of the die of Fig. 3 with a holder there'- for, both partly in section; this holder having means for centering the die, for preventing rotation of the die therein and means for locking the die in adiusted position; Fig. 5 is a view similar to Fig. 4 but showing an- Y other form of cap which is provided with a guide for accurately centering the work relatively to the die, and Fig. 6 is a detail sectional view ofthe cap shown assembled in Fig. 5.

The die 25. shown in Figs. 1 and 2, has a base 31 provided with a plane face 44 and Specication of Letters Patent.

like reference characters Patented Jan. 16, 1917. serial No. 33,946.

has, extending from the base, prongs 29 upon which the cutting thread is formed. The axis of the cutting thread is perpendicular to the plane face 44, being so formed by the method of manufacture of the die. Upon the free ends of the prongs are cone surfaces accurately machined coaxially with the thread. The die holder 39 is provlded with a conically threaded recess having a finished plane seat 46 at its smaller end; the thread being coaxial with the axis of the holder and the seat being perpendicular thereto. To assist in retaining the die 1n position, a. conically threaded clamping thimble 35 is provided, this thimble fitting the conical recess above mentioned and being split by a longitudinal saw cut at 17. After the thimble 35 has been partially screwed into the holder 39, the die 25 is inserted in the central opening of the thirnble and is pushed through until the plane face 44 of the die bears against the plane seat 46 of the holder. The thimble 35 is then screwed farther into the recess, the taper threads and saw 35 to contract and hold the die in position in the holder. The recesses 40 on the thimble provide for the application of a Spanner wrench for screwing the thimble into final position in the holder. The die is also held in the holder by the cap 41 which is then screwed on to the holder 39; the internal threads on the cap 41 engaging the external threads upon the'die holder 39. rll`he cone surfaces 45 of the prongs coact with the coincident frusto-onical surface 47 of the cap 41 so that, in addition to aiding in the retention of the plane face of the die against the plane seat of the holder. the prongs of the die are sprung into position to cut the desired size of thread and it is assured that. in any adiusted position of the cap. each prong will do its proportionate share of the cutting and. therefore, maintain the accuracy of the lead of the screw. To facilitate the adiustment of the cap. recesses 42 are formed therein to be engaged by a Spanner wrench. rThis cap 41 has apertures 43 which provide means for supplying oil to the cutting surfaces of the die and they also allow the chips to pass through them from the work. At the iunction ofthe die prongs 29 with the base 31. it will be noticed that there are recesses 27 'llhese recesses leave cut 17 causing the thimble llO the faces 33 of the prongs 29 in relief so that, when the die prongs are ground, there is a clearance for the grinding tool at the root of the prongs, which clearance saves wear on the grinding tool and increases the ease and speed of sharpening the die.

Referring to Figs. 3 and 4, the die there shown also has a base 51 provided with a finished plane face 64 which'is at right angles to the axis of the cutting thread. The holder for this die is provided with a plane seat 66 at right angles to its axis. In this construction of die and holder, however, this face and seat are held together entirely by the cap, here numbered 61, and the die' is poe vented from turning in the holder by a groove 77 provided in the face 64, which groove engages the flattened sides 73 of pins 75 in the holder 59.4"'While the pins serve to prevent the die from rotating relatively to the holder, this pin-and-slot connection between the face 64 and seat 66 permits the die to adjust itself transversely of the axis of the holder during the tightening of the cap 61 and it will be seen that the die is thus free to position itself in perfect alinement `with the holder 59 andthe cap 61. This construction insures a concentric initial relation between the dieand the holder and, when the cap is thereafter adjusted, a uniform pressure will be exerted on all the die prongs by the cone surfaces 65 of the prongs coacting with the cone surface 67 of the cap 61. This causes the prongs to penetrate equally into the work and maintain an accurate lead on the screw being cut, asdescribed in connection with the construction illustrated in Fig. 2. There is also provided a collar or check nut 79 which prevents the cap 61 from turning on the threaded part of the holder 59 and altering the size of the thread that will be cut by the die after the cap has been adjusted. Ordinarily, without such cheeknut, the starting and stopping of the threading operation might tend, with such a construction, to move the die slightly in the holder, and thereby move the cap and alter the adjustment of the die prongs but with the collar or check nut 79 coacting with the cap 61, any disturbance of the adjustment is prevented.

The form of cap 81 shown in Figs. 5 and 6 is particularly useful when a' hand stock or bit brace is to be used because it is provided with a guide for accurately centering the work relatively to the die. This guide may be integral with the cap but consists, in the preferred construction, of a bushing 91 removably secured in an opening in an extension of the cap 81, thc inside diameter of the bushing being such that the Work upon which the thread is to be out will pass through it freely but not too loosely. This bushing is held in position by a set screw 93 and can be readily removed and another size substituted when the size of work is changed. If the bushing is not used, a different cap must be used whenever the size of work is changed. It will be seen that, as these parts are machined coaxially with the cone surface 87 of the cap, there is no liability of the work entering the die in ,an oblique direction. @penings 83 are provided in this cap so that oil or other lubricant may be supplied to the cutting surfaces of the die and so that the chips may pass through them away from the work. The remaining parts shown in Fig. 5 have .the same construction as those shown in Fig. 4.

The Shanks or spindles (illustrated at 37 in Fig. 2 and at 57 in Figs. 4 and 5) of the die holders may be of any size or shape suitable for use in a screw machine, lathe, hand stock, bit brace or any other suitable means for operating threading dies.

Vith respect to the common subject-mat ter, this application is a continuation, in part, of my application, Serial No. 658,871, filed November 6, 1911, for Letters Patent for improvements in threading dies and holders.

Having described my invention, what I claim as' new and desire to secure by Letters Patent of the United States is 1. The combination of a threading die having a base provided with a plane face and having prongs extending from the base, the prongs being provided with a cutting thread the axis of which is perpendicular to said plane face, a die holder having a plane seat, and a cap for the holder constructed and arranged to hold the plane face of the die against the plane seat in the holder and also constructed and arranged to adjust the depth of cut of the die by the position of said cap upon the holder.

2. The combination of a threading die having a base provided with a plane face and having prongs extending from the base, the prongs being provided with a cutting thread the axis of which is perpendicular to said plane face, a die holder having a plane seat perpendicular to its axis, and a cap for the holder constructed and arranged to hold the plane face of the die against the plane seat in the holder and also constructed and arranged to force the prongs together to increase equally their penetration into the work.

3. The combination of a threading die having a base provided with a plane face and having prongs extending from the base, the prongs being provided with cone sur-4 faces and with a cutting thread the axis of which is perpendicular to said plane face, an externally threaded die holder having a plane seat perpendicular to its axis, and an internally threaded cap for the holder, said cap having a cone surface thereon constructed and arranged to engage the cone surfaces tatami of the prongs and spring said prongs in order to vary equally their depth of cut, said cap being also constructed and air-, ranged to hold the plane face of the dief against the plane seat in the holder.

4. Thread cutting apparatus, having, in combination, a pronged threading die, a die holder and a cap, said die and holder having a sliding connection constructed and arranged to permit the die to traverse the axis of the holder transversely to position the die and cap initially in concentric relation and'so that adjustment of the cap causes an equal penetration of each prong of the die into the work.

5. The combination of a pronged threading die, a holder therefor, a cap for said holder, means constructed and arranged to permit the die to `move transversely in the holder and to prevent relative angular movement between the die and holder, said die, holder and cap being constructed and -arranged to bring the die into coaxial alinement with the holder and then to force the prongs of the die together to increase their penetration into the work.

6. The combination of a pronged threading die, a holder therefor, a cap for said holder, means constructed and arranged to permit the die to movel transversely in the holder and to prevent relative angular movement between the die and holder, vsaid die, holder and cap being constructed and arranged first to bring the die into coaxial alinement with the holder, then to clamp it in position and finally to force the prongs of the die toward each other to increase4 equally their penetration into the Work.

7. The combination of a pronged threading die, a holder therefor, a cap for said holder, means constructed and arranged to permit the die to move transversely in the holder and to prevent relative angular movement between the die and holder, said die, holder and cap being constructed and arranged first to bring the die into coaxial alinement with the holder, then to clamp it in position, finally to adjust the prongs of the die to the proper depth of cut, and means for locking the holder and cap in adjusted position.

8. As an article of manufacture, a threading die having, in combination, a base provided with a groove and a plane face and having prongs extending from the base, the prongs being provided with a cutting thread the axis of which is perpendicular to said plane face.

9. An article of manufacture, having, in combination, an externally threaded holder for a pronged threading die, a plane seat in the holder perpendicular to the axis of the holder for supporting a die, means for preventing a die from turning in the holder, an internally threaded cap for said holder,

the cap being provlded with acone surface to engage a die, and means for locking the cap in position upon the holder.

10. An article of manufacture, having, in combination, a holder yfor a pronged threading die, a cap for said holder, said cap having a cone-shaped surface constructed and arranged to engage corresponding cone surfaces onv the prongs of the die, and a guide forthe work located on the cap and coaxial with said cone surface.

11. An article of manufacture having, in combination, a holder for a pronged threading die and an internally threaded cap for said holder, said cap having a cone-shaped surface constructed and arranged to engage ,corresponding cone surfaces on the prongs of the die, said cap also being constructed and arranged to guide the work in co-axial relation to the die.

12. An article of manufacture, having, in combination, a holder for a pronged threading die, a cap for said holder, said cap having an extension and a cone-shaped surface constructed and arranged to engage corresponding cone surfaces on the prongs of a cutting die, a bushing in said extension and coaxial with said cone surface, said bushing being removably secured in said cap and serving to guide the work to the die.

13. Thread cutting apparatus, having, in combination, a pronged threading die, a die holder and a cap, said die and holder having a sliding connection constructed and arranged to permit the die to traverse the axis of the holder transversely to position the die and cap initially in concentric relation and so that adjustment of the cap causes an equal penetration of each prong of the die into the work, and means, carried by the cap, for guiding the work to the die.

14. The combination of a threading die having a base provided with a plane face and having prongs extending from the base, the prongs being provided with cone surfaces and with a cutting thread the axis of which is perpendicular to said plane face, an externally threaded die holder having a plane seat perpendicular to its axis, and an internally threaded cap for the holder, said cap being provided with apertures for the passage of lubricant and chips and also being provided with a cone surface constructed and arranged to engage the cone surfaces of the prongs and spring. said prongs in order to vary equally their depth of cut, said cap being also constructed and arranged to hold the plane face of the die against the plane seat in the holder.

15. A threading die and holderconstructed and arranged for relative transverse movement of the die in a plane perpendicular to the axis of the holder While the die is being positioned in the holder.

16. The combination of a threading die having a base provided with a plane face and having prongs extending from the base, the prongs being provided with a cutting thread the axis of which is perpendicular to said plane face, a die holder having a plane seat, a cap for the holder constructed and arranged to hold the plane face of the die against the plane seat in the holder and also constructed and arranged to adjust the depth of cut ot' the die by the position of said cap upon the holder and means for preventing relative angular movement between the holder, cap and die.

17. The combination of a threading die having a base provided with a plane face and having prongs extending from the base, the prongs being provided with a cutting thread the axis of which is perpendicular to said plane face, a die holder having a plane seat perpendicular `to its axis, a cap for the holder, said cap being provided with apertures for the passage of lubricant and chips and constructed and arranged to hold the plane face of the die against the plane seat in the holder and also constructed and arranged to force the prongs together to increase equally their penetration into the Work and means for preventing relative angular movement between the holder, cap and die.

18. The combination of a threading die having a base provided with a plane face and having prongs extending from the base, the prongs being provided with cone surfaces and with a cutting thread the axis of which is perpendicular to said lane face, said prongs being recessed at their junction with the base, an externally threaded die holder having a plane seat perpendicular to its axis, and an internally threaded cap Jfor the holder, said cap having a cone surface thereon constructed and arranged to engage the cone surfaces of the prongs and spring said prongs in order to vary equally their depth of cut, said cap being also constructed and arranged to hold the plane face of the die against the plane seat in the holder.

In testimony whereof I have signed my name to this specification.

HENRY M. LOOMER. 

